Do Islamic inheritance rules automatically apply in the UK?

No, Islamic inheritance rules do not automatically apply in England and Wales. English law gives you complete freedom to leave your estate to anyone you choose, but it does not enforce Islamic principles unless you specifically choose to follow them in your will.

Without a proper Islamic will, your estate would be distributed according to English intestacy law if you die without any will, or according to whatever you specify in a standard will.

This is why Muslims living in the UK need to make an Islamic will - it's the only way to ensure your estate is distributed according to Islamic principles and English law requirements at the same time.